a criminal complaint says deputy r.l.
henderson then was given a field sobriety test , which deputies said he failed .
henderson , 56 , of elkhorn was arrested and charged with dui ( cdl ) and defective equipment .
henderson is employed by the department .
the mcdowell county sheriff 's department says thomas keith henderson of elkhorn was arrested late wednesday during a traffic stop on burke mountain near keystone .
the deputy said when he spoke with the driver , thomas keith henderson , he could smell alcohol on henderson 's breath .
the plow was on route 6 at the top of burke mountain near keystone at the time .
deputies said that the legal limit for cdl operators is .04 .
at the welch police department , henderson was given a breathalyzer test which registered his blood alcohol content at .090 .